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Thanks for response, Anonymous, you wrote: “”Evolution by "group selection" may act upon mean collective survival but is rare in nature (social insects, naked mole rate?, but has not been rigorously applied to humans.””

This has nothing to do with group selection. Selection is on the individual level under the assumption that sufficiently many quantitative characters are Gaussian distributed due to the additive effect of genes and that the rules of genetic variation may act as random number generator for the Gaussian distributed characters.

Further you wrote: “Individuals in a group could never contribute equally to collective survival. Some in the group can be considered detriments as competators for resources and vectors for disease. Increasing population densities leave a group vulnerable to epidemics and famine.”

If mating is approximately random and the centre of gravity of the offspring’s Gaussian distributed characters coincides with ditto of parents according to the Hardy-Weinberg law, then, according to the theorem of Gaussian adaptation (GA), the mean fitness and “average information” of the collective are simultaneously maximal and all parents “contribute equal to the centre of gravity of the characters”. The detriments, the vulnerable epidemics and famine have no impact on this, but may possibly make the region of acceptability, A, in phenotypic space, smaller. But because the theorem of GA is valid for all Gaussians and all A independent of structure and extension, they have nothing to do with this. The collective survival is still maximal with respect to the circumstances you mentioned.

On the other hand, if characters are not Gaussian distributed or if the law of Hardy-Weinberg is not applicable, then mean fitness can, to my knowledge, only be approximately maximized.

Gkm